The tyrosine phosphatase SHP-1 promotes T cell adhesion by activating the adaptor protein CrkII in the immunological synapse

• Published in: Science signaling 2017-08, Vol.10 (491)
• Main Authors: Azoulay-Alfaguter, Inbar, Strazza, Marianne, Peled, Michael, Novak, Hila K, Muller, James, Dustin, Michael L, Mor, Adam
• Format: Article
• Language: English
• Subjects: Adaptive Immunity; Animals; Cell Adhesion; GTPase-Activating Proteins - genetics; GTPase-Activating Proteins - metabolism; Guanine Nucleotide-Releasing Factor 2 - genetics; Guanine Nucleotide-Releasing Factor 2 - metabolism; HEK293 Cells; Humans; Immunological Synapses - immunology; Immunological Synapses - metabolism; Jurkat Cells; Lymphocyte Activation - immunology; Lymphocyte Function-Associated Antigen-1 - metabolism; Mice; Mice, Transgenic; Phosphorylation; Primary Cell Culture; Protein Tyrosine Phosphatase, Non-Receptor Type 6 - genetics; Protein Tyrosine Phosphatase, Non-Receptor Type 6 - metabolism; Proto-Oncogene Proteins c-crk - genetics; Proto-Oncogene Proteins c-crk - metabolism; Receptors, Antigen, T-Cell - metabolism; Single-Cell Analysis; T-Lymphocytes - immunology; T-Lymphocytes - metabolism
• ISSN: 1945-0877; 1937-9145
• DOI: 10.1126/scisignal.aal2880

The adaptor protein CrkII regulates T cell adhesion by recruiting the guanine nucleotide exchange factor C3G, an activator of Rap1. Subsequently, Rap1 stimulates the integrin LFA-1, which leads to T cell adhesion and interaction with antigen-presenting cells (APCs). The adhesion of T cells to APCs is critical for their proper function and education. The interface between the T cell and the APC is known as the immunological synapse. It is characterized by the specific organization of proteins that can be divided into central supramolecular activation clusters (c-SMACs) and peripheral SMACs (p-SMACs). Through total internal reflection fluorescence (TIRF) microscopy and experiments with supported lipid bilayers, we determined that activated Rap1 was recruited to the immunological synapse and localized to the p-SMAC. C3G and the active (dephosphorylated) form of CrkII also localized to the same compartment. In contrast, inactive (phosphorylated) CrkII was confined to the c-SMAC. Activation of CrkII and its subsequent movement from the c-SMAC to the p-SMAC depended on the phosphatase SHP-1, which acted downstream of the T cell receptor. In the p-SMAC, CrkII recruited C3G, which led to Rap1 activation and LFA-1-mediated adhesion of T cells to APCs. Functionally, SHP-1 was necessary for both the adhesion and migration of T cells. Together, these data highlight a signaling pathway in which SHP-1 acts through CrkII to reshape the pattern of Rap1 activation in the immunological synapse.